Objective

To run 44 Ugi reactions all involving phenanthrene-9-carboxaldehyde in THF at 1M final concentration of the reactants in the reaction mixture. The results will serve to improve a model for predicting selective precipitation of a Ugi product from a reaction.


Results

Spreadsheet-UCExp238
vials with clear solution -day 1
vials with ppts - day 2

Conclusion

Few reactions formed precipitates and others remained clear.

Log

2009-07-11

15:30 Weighed out [Cedric] phenanthrene-9-carboxaldehyde (8mmol, 1.65g) and made-up a 2M solution in THF in a 4mL volumetric flask (Cedric). Initially it was difficult to dissolve the solid completely in the solvent, however the volumetric flask with the contents was placed in a sonicator, water bath temperature was around 30C.
15:50 All the solid in the above phenanthrene-9-carboxaldehyde dissolved completely and a homogeneous solution was obtained. (Note:Temp in the lab was recorded to be 20C).
16:10 Weighed out [Cedric] crotonic acid (20mmol, 1.722g) ; phenyacetic acid (20mmol, 2.723g) and Boc-glycine (20mmol, 3.503g) and dissolve the solid in THF in three 5mL volumetric flasks, to make 4M solutions of the acids in THF. To obtain a homogeneous solution of Boc-glycine it was placed in a sonicator.
16:20 Boc-glycine formed a homogeneous solution in THF upon sonication (water bath temp ~30C.
16:30 Labeled half dram vials with screw tops 1-72 (only 44 were used)
16:45 Started pipetting out amine in to vial...see spreadsheet for vial number and corresponding chemical and the volumes added to each via
16:50 It was difficult to pipette out phenanthrene-9-carboxaldehyde (2M in THF) solution because a) the solid appeared to be precipitating out b) the solvent appeared to be evaporating, c) the pipette tip kept clogging and had to be replaced very often.
Only 44 reactions were performed because it was difficult to pipette out the aldehyde solution.
Note to self : Do not try to use 2M solution of phenanthrene-9-carboxaldehyde in THF, especially when the room temperature is 20C....a 1.5M solution may be reasonable.[that is probably a good idea JCB]
17:00 Solvent in some of the vials dried out even before acid and isocyanide addition. (failed dissolution) [you started out with a solution so is this due to precipitation after addition of the amine? JCB] Precipitation, probably occurred because of a) solvent evaporation and b) as a result of a reaction of the aldehyde with the amine. It would be best if these reactions were carried-out with more solvent, i.e at a lower concentration, may be 0.7-0.8M final concentration per component.
17:20 Some reaction vials that contained clear solutions had already formed some sort of ppts. (precipitated reaction)
17:30 Obtained some more pictures of the reactions. (vials with clear solution)

2009-07-12

20:18 Some twelve vials appear to have solid formed in them. Obtained a picture of the vials which had solid ppts in them.
20:20 The remaining vials which contained clear solutions were vortexed for 10s each and left on the bench top tightly capped.